Quantifying Matting Agent Displacement in Package Printing Overprint Coatings
Quantifying matting agent displacement requires z-axis Raman depth profiling and strict viscosity recovery control to stop gloss drift and scuff failure.
Particle Migration
Mass Transfer
Transport phenomena describe the movement of microscopic fragments or synthetic components from a packaging material into the packaged product. The process of particle migration is a risk when recycled fibers are used in direct contact with food. It involves the translocation of discrete particulate matters such as microplastics or inorganic pigment residues.
Physical Driver
Mechanical factors such as temperature, pressure, vibration and physical abrasion during transport accelerate this transfer of particles across the packaging interface. In paperboard, loosely bound mineral fillers or synthetic sizing agents can detach from the fibre matrix and settle onto dry food grains or powders. When the packaging is exposed to high humidity or elevated temperatures, the risk of this movement increases because the fibrous network swells and releases bound contaminants.
For this reason, converters utilize internal bags or polymer coatings to create a physical block that intercepts these particles before they reach the product.
Barrier Performance
Analytical laboratories evaluate this behavior by using food simulants that mimic the extraction properties of different food types. Solid food simulants like modified polyphenylene oxide or liquid starches are incubated with the packaging material under controlled temperature and time conditions. Measuring the level of particle migration ensures that the packaging complies with food contact safety regulations and prevents contamination that could alter the taste, odour or chemical safety of the product.